The invention relates to a tubular shaft instrument.
In modern medicine, attempts are generally made to keep the damage to intact tissue to a minimum. Thus, when circumstances permit, minimally invasive surgery is usually the preferred method used to perform an operative intervention. Small incisions and little trauma to the tissue lead to a lower sensation of pain after the operation and to rapid recovery and mobilisation of the patient. This also applies to laparoscopic surgery during which complex operations are performed in the abdominal cavity.
Operations of this type and the instruments required for them present a particular challenge to the manufacturers of medical instruments as the majority of the operative steps are performed in very restricted spaces and without direct visual contact. Thus the medical instruments used must not only be able to operate in the smallest spaces but must also function so reliably that visual monitoring is superfluous. The instruments are preferably constructed such that even without visual contact the operating surgeon always has feedback which enables him to draw conclusions about the progress of the operation.
Tubular shaft instruments are known which comprise a handle, a tubular shaft and at least two mouth parts. These tubular shaft instruments are suitable for gripping and fixing tissue. These tubular shaft instruments frequently have other functionalities. Thus, EP 1 211 995 B1, for example, discloses a tubular shaft instrument having corresponding mouth parts which applies high-frequency (“HF”) current to the fixed tissue in order to coagulate it. It is also known to provide such tubular shaft instruments having a cutting device for separating the gripped tissue.
As tubular shaft instruments are used in very restricted regions of the body, they must be kept as small as possible. Nevertheless, as already observed, a reliable method of functioning and a high level of functionality must be guaranteed. Thus, amongst other things, it is problematic to ensure a sufficiently steady transmission of force for operating the mouth parts.
The same reference numerals are used in the following description for identical parts and parts acting in an identical manner.